Feeding mechanism for sewing machines



NM), 27, 319289 I 1,693,524

- R. MUNDLQS FEEDING MECHANISM FOR SEWING MAGHIEE S Filed Jan. 26, 1927Patented Nov. 27, 1928.

HQE

RUDOLF MUNDLOS, OF MAGDEBURG, GERMANY.

FEEDING MECHANISM FOR SEWING IVIAGHII Q'ES.

Application filed J'anuary.26, 1927, Serial No. 168,756, and in GermanyApril 29, 1925.

This invention relates to feeding mechanism for sewing machines by meansof which either usual stitches or zig-zag lines of stitches can be made,i. e. in which the material feeder executes a movement in thelongitudinal direction of the machine, a movement transversely to thefirst movement,

. and a reciprocating movement in vertical direction.

The invention has for its object to improve the driving mechanism forthe materialfeeder for such machines and to provide a sewing machine ofsuch construction that the samewill be capable in operation to makestitching which may be either of the zig-zag type or'straight stitches.

The means for actuating the material feeder includes .an oscillatingmember or link which transmits its. movement by 2. connect-.

ing rod 11 upon a frame-shaped slide 12, with which the material feeder20 is connected. The oscillating shaft 18 has arms which carry anoscillating bolt 16. This oscillating bolt 16 is connected to theframeshaped slide 12 and the material-feeder 20 is fixed on the same. Bythe movement of the frame-shaped slide a longitudinal movement isimparted to the material-feeder, a transverse movement being imparted tothe same by the oscillating of the shaft 18.

In this form of construction the number of moving parts are reduced to aminimum. It presents further the advantage that, when the frame-shapedslide 12 is locked in one of its positions, the machine can be used forusual stitching. Special means are provided to hold the frame-shapeslide in the most convenient position for stitching, as will behereinafter explained with reference tt};the

. figures of theaccompanying drawings in which Fig. 1 shows a rearelevation of the machine and Fig. 2 is a plan view seen from below, Themain shaft 1 is journaled in bearings 2 and 3 which are fixed on themachine frame. On this main shaft is secured a pinion 4 which mesheswith a spur wheel 6 held in a bearing 5. Rigid with this spur wheel 6 isa cam disk 7 which guides a stud 9 of a lever 10. This lever 10ispivoted upon a bolt 8 and is given an oscillating movement when thestud 9 is moved by the cam which is attached to the spur wheel 6. Oneend 11 of a connecting rod is secured in a curved slot of the lever 10.This connecting rod is composed of two parts 11 and 11 which slide oneinto the other and held together by the action of a spring 11 The part11 of the connecting rod is pivotally mounted on the frame-shaped slide12, and by adjustmg the rod 11 in the lever 10 the amplitude ofthemovement of the frame-shaped slide 12 is regulated. The frame shapedslide 12 engages guides 13, and it has a roller 14 over which is locateda fork -15. This fork 15 is mounted on an oscillatable bolt 16 carrledby two arms 17 which project from an oscillatable shaft 18. This shaft18 is journaled at its ends on points 18*. The oscillatable bolt 16carries, besides the fork 15, a holder 19 of a material-feeder 20.

The reciprocating movement of the frameshaped slide 12 is transferred bythe fork 15 and by the holder 19 to the'material-feeder' 20, at the sametime that a movement transversely to the longitudinal direction of themachine is communicated to said materialfeeder by the oscillatingmovement of shaft 18 and consequently of the arms 17 and of the bolt 16.The lifting movement of the material-feeder is controlled by a cam 21 onthe main shaft 1 and by the oscillating shaft 18 to which it isconnected, in a well known manner, and is driven from the main shaft 1by-a lever system which acts upon a lever or arm 22 on said shaft 18.

When the machine has to be used for straight stitching, a guide frame 25is mounted on the machine frame as shown in Figs. 1 and 2,-which. guideframe has a curved portion 26. The part 11 of the connecting rod, facingthe frame-shaped slide carries, between the frame-shaped slide 12and thelever 10 on its upper side an abutment pin 27 which, in certainpositions,

strikes against the curved portion 26 of guide 25 to which is pivoted alever 28- which may be operated by the knee of a person using themachinethrough the intermedia of a depending knee lever 31, its elbow lever 30and a connecting rod 29, equivalent means may be used to move the lever28 into'and out of engagement with the slidable frame The mechanismdescribed serves in part w for straight or ordinary back stitching, and

it operates in the following manner: en the edge of the goods has beenfolded, and thread used for stitching is adjacent to the outer edge ofthe seam, the material-feeder 20, or the frame-shaped slide 12, has tobe brought into the outer dead center position.

This is eifected b the knee actuated lever 31 which, through t eintermediary of the lever system 30, 29, 28,.pushes the frame-shapedslide 12 into its extreme right hand dead center position. At thismovement of the frame-shaped slide 12the part 11 of the connecting rodis pulled away from part 11, in opposition to the action of spring 11neither the lever 1-0 nor the cam -7 being impeded as to theiroscillating or rotating movements.- 1 V The length of the stitchesdepends on the stroke of the frame-shaped slide 12 and this strokedepends on the position of the connecting rod'11 with the lever 10 andthe position of the adjustable stud pin or oolt which adjustablyconnects the end of the rod 11 withthe slotted lever 10. When the rod isin the position shown in Fig. '2, the stroke of the frame-shaped slideis near its limit for producing the longest stitches, and

when the frame-shaped slide 12 is shifted by means of the knee lever 31it would, owing to the yieldability of the connecting rod 11 be pushedtoo far in outward direction. In order to prevent this the curvedportion 26 of the guide 25' and the abutment pin 27 on part 11 of theconnecting rod are provided. The curved portion 26 is constructed sothat the'frame-shaped slide can be brought, by meansof the knee operatedrod 31, only into an outer extreme position which corresponds to theactual stroke or to the actual position of the connecting rod 11 in thelever 10. r

A sewing machine of the character set forth and illustrated may be usedfor ordinary sewing by simply moving the bar 11 to the oppositeend ofthe slot through the lever 10, in which position it may beheld by aclamp bolt the shank of which passes through the slot of thecameactuated lever .10, and when so positioned and held, the

mechanism for producing zigzag stitches will be'inoperative and themachine operates to produce straight stitches.

The stitching mechanism for ordinary straight stitching is not shown, as'it is of well known construction, being of the rotary shuttle type,and, in connection therewith,

it may be stated that the needle fplate has a transverse slot for thepassage 0 the needle and that lateral movement is imparted thereto. Thepresser foot is" also provided with a slot, as the needle carried by theneedle bar and the presser foot are each transversely slitted so thatthe needle may pass through the same and the work.

I claim:

1. In a sewing machine for moving a material-feeder inlongitudinaldirection comprising a main shaft, a material-feeder, abearing on the main shaft, an oscillatable lever, a frame-shaped slideassociated with.

the main bearing and with the materialfeeder, a connecting rod betweensaid lever and material slide, a stud projecting from the slide, anoscillatable bolt on which the material feeder is pivotally mounted, anda ting: on said bolt for engagement with said s 1 e.

- 2.'The combination in a sewing machine having means whereby thestitches 'produced may be either zig-zag or straight, of a cam actuatedlever having therein a segmental slot, a sliding frame associated withthe cam actuated lever, a two part connecting bar the two parts of whichare slidablyconnected, 2; spring attached to each of the .for adjustablyattaching one end of said two part connecting bar with the cam .actuatedlever.

3. In a sewing machine, the combination of a slide mounted forreciprocation and associated with stitch controlling means, saidcontrolling means comprising a roller carried by said slide, a shaftmounted for oscillation,'a fork which engages the roller, a materialfeed mounted for movement on the shaft which carries said fork, a mainshaft, a cam thereon for actuating the material feed, and means drivenfrom the main shaft and connected. with the slide by means of which thematerial feed can be set and actuated for either straight or zig-zagstitches. a

41. In a sewing machine having means for producing either straight or zigzag stitches, Y

a frame-shaped slide mounted for reciprocation at right angles to thedirection of the material feed, manually adjustable mdans comprising alever which'is adapted to restrict movement of the slide by engagementtherewith, a main drive" shaft having thereon means for actuation of amaterial feed and a cam disk, anv oscillatory lever which engages thecam disk, a two part connecting rod, one of the parts thereof beingadjustably connected to the lever and the other part pivotally connectedto the slide, and a spring eonnectin the two partsof the connecting rodtoget er.

5. The combination in a sewing machine of the zigzag stitch type, of amain rotary shaft, a rock shaft, a material feed operated in part byboth of the aforesaid mentioned ing aIp rojecting stud, a fixed framewith which the stud may be positioned to engage a portion of the saidfixed frame and thereby 10 control movement of the slide.

In testimony whereof I afiix my signature.

RUDOLF MUN DLOS.

